1. Technical Field
The present invention relates generally to the measurement of flow parameters of a multiphase fluid, and more particularly to methods and apparatus for determining the existence of stratification within the flow, and for measuring gas and liquid flow rates in a stratified flow.
2. Background Information
Many industrial fluid flow processes involve the transportation of multi-phase fluid flows through a pipe. In applications where the fluid flow travels within a pipe having a substantially horizontal centerline, the fluid flow may be subject to some degree of stratification, where gas and liquid separate into different layers. The layers are separated by a distinguishable interface and the gas flows on top of the liquid. Stratification of flow is based on many parameters such as, flow rate, gas to liquid ratio, angle of pipe, and pressure.
There is considerable value in being able to accurately determine the flow rate of the liquid and gas components in a stratified flow. In an oil and gas application, for example, determining the flow rates of the oil and gas can facilitate the processing of each component. There is particular value in the ability to determine the flow rate of the liquid and gas components in a stratified flow in a non-invasive manner. What is needed, therefore, is a method and apparatus operable to determine the component flow rates within a stratified fluid flow in a non-invasive manner.